A modified reciprocal reflection interferometer (MRRI) is proposed for vibration insensitive optical fiber current sensors (OFCSs). The verifications of experiments are in good agreement with our theoretical analyses. A large vibrational perturbation applied to a segment of lead fiber to simulate the disturbance to the OFCS can be suppressed over 20 dB compared with a conventional reciprocal reflection interferometer (RRI). The noise floor of the OFCS with an MRRI under perturbations is about 1.36 Arms turns/Hz1/2 near the shot noise limit. A good linear demodulation result is obtained and the evaluation of the Verdet constant 1.1 μrad/Arms turns approximates the literatural data measured in static environment. © 1999 Society of Photo-Optical Instrumentation Engineers.